A sound reinforcement system is a widely-used device in the modern society. However, when the sound from a speaker gets back to a microphone, an acoustic feedback occurs. The acoustic feedback is detrimental to the performance of the sound reinforcement system.
FIG. 1 schematically illustrates the architecture of a conventional sound reinforcement system. As shown in FIG. 1, the sound reinforcement system includes a microphone 13 and a speaker 15. When a sound such as “1, 2, 3 . . . ” is issued by a user 11, the sound is received by the microphone 13, then amplified, and finally outputted from the speaker 15.
However, at the time when the sound is received by the microphone 13, the amplified sound is simultaneously outputted from the speaker 15. The sound from the speaker 15 is also received by the microphone 13. That is, the feedback audio received by the microphone 13 includes two separate sounds. The two sounds include a target audio originated from the user 11 and a background audio from the speaker 15.
The loop of receiving, amplifying and outputting the sound may result in the acoustic feedback and the acoustic divergence. When the acoustic feedback occurs, the speaker is readily damaged. The acoustic feedback may lead to a howling sound, which is unpleasant to the user 11 and the listener.
Conventionally, a low-sensitivity microphone is used to prevent the microphone from receiving the background audio in order to reduce the influence of the acoustic feedback. Although the use of the low-sensitivity microphone can solve the problems of resulting in the acoustic feedback and the howling sound, there are still some drawbacks. For example, since the low-sensitivity microphone is only able to receive the sound at a very short distance, the microphone has to be located near the mouth of the user. Generally, since the low-sensitivity microphone is a handheld microphone, a neck-worn microphone or a head-worn microphone, the use of the low-sensitivity microphone is inconvenient.
Moreover, since the microphone is located near the mouth of the user, the droplets and the saliva of the user are readily retained on the microphone. In other words, the use of the low-sensitivity microphone is unsanitary.
In accordance with another way of reducing the influence of the acoustic feedback, the sound volume of the speaker is decreased or the microphone is placed far from the speaker. Consequently, the influence of the sound from the speaker on the sound-receiving performance of the microphone is reduced. However, since the sound volume of the speaker is decreased, the efficacy of amplifying the sound by the speaker is impaired. Moreover, in many situations, the position of the speaker cannot be arbitrarily moved.
Therefore, there is a need of providing an audio adjusting method and an acoustic processing apparatus in order to reduce the influence of the acoustic feedback of the reinforcement system.